Members of Britain’s main teaching union have voted to go on strike over the “erosion” of their pay and working conditions on the eve of the annual TUC Conference.

In a decision which will inflame tensions with ministers the National Union of Teachers (NUT) said a ballot of its members had shown that 82.5 per cent were in favour of walkouts, with a turnout of 27 per cent.

The result raises the prospect of significant disruption to schools later this term. The union has suggested it would coordinate action with the NASUWT teachers’ union which already has a mandate to take industrial action.

The ballot result follows a warning by the leader of the UK’s biggest trade union of a fresh wave of co-ordinated strikes because of continuing anger over cuts to pay and pensions which was leading the country on a “path to poverty”.

Len McCluskey, general secretary of Unite, said there was a “real likelihood” of more industrial action before the end of the year, following last November’s huge walkout by public sector workers over the Government’s controversial pension reforms.

He said the pensions issue remained a “festering sore” among workers in the health service, education and civil service and could erupt again in the coming months, he said.

The annual TUC Congress is being held next week in Brighton, when activists are expected to press for industrial action.

Mr McCluskey said public sector workers had endured a three-year pay freeze and face another two years without any increase.

“The attacks on public sector workers are unfair, and our members remain furious and angry,” he said.

“There is a real chance of coordinated industrial action, if not this winter, then early next year.”

NUT general secretary Christine Blower added: “The NUT is left with no option but to take action to protect the well-being of our members and restore their rights to do their job thoroughly and properly.

“Teachers are being undermined by a Government whose almost daily criticisms and erosion of working conditions and pay, coming on top of previous attacks on pensions, are unacceptable. This negative approach to the profession has to stop.”

But the new Conservative Party Chairman Grant Shapps condemned the strike threat.

“Labour’s single biggest union paymaster is threatening British businesses with mass strikes as his trade union continues its takeover of the Labour Party,” he said.

“Ed Miliband must refuse to take a single penny more of this union baron’s cash until Len McCluskey withdraws his irresponsible threat to sabotage our economy.”